Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 83081 

751(a)(1) and 777(i)(1) of the Act, and 19 

CFR 351.213(h) and 351.221(b)(5). 

Dated: November 20, 2023. 

Abdelali Elouaradia, 

Deputy Assistant Secretary for Enforcement 

and Compliance. 

[FR Doc. 2023–26135 Filed 11–27–23; 8:45 am] 

BILLING CODE 3510–DS–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XD494] 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to the City of 

Oceanside’s Harbor Fishing Pier and 

Non-Motorized Vessel Launch 

Improvement Project in Oceanside, 

California 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; proposed incidental 

harassment authorization; request for 

comments on proposed authorization 

and possible renewal. 

SUMMARY: NMFS has received a request 

from the City of Oceanside for 

authorization to take marine mammals 

incidental to pile driving activities 

associated with harbor fishing pier and 

non-motorized vessel launch 

improvement in Oceanside, California. 

Pursuant to the Marine Mammal 

Protection Act (MMPA), NMFS is 

requesting comments on its proposal to 

issue an incidental harassment 

authorization (IHA) to incidentally take 

marine mammals during the specified 

activities. NMFS is also requesting 

comments on a possible one-time, 1- 

year renewal that could be issued under 

certain circumstances and if all 

requirements are met, as described in 

Request for Public Comments at the end 

of this notice. NMFS will consider 

public comments prior to making any 

final decision on the issuance of the 

requested MMPA authorization and 

agency responses will be summarized in 

the final notice of our decision. 

DATES: Comments and information must 

be received no later than December 28, 

2023. 

ADDRESSES: Comments should be 

addressed to Jolie Harrison, Chief, 

Permits and Conservation Division, 

Office of Protected Resources, National 

Marine Fisheries Service and should be 

submitted via email to ITP.clevenstine@

noaa.gov. Electronic copies of the 

application and supporting documents, 

as well as a list of the references cited 

in this document, may be obtained 

online at: https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/incidentaltake-authorizations-constructionactivities. In case of problems accessing 

these documents, please call the contact 

listed above. 

Instructions: NMFS is not responsible 

for comments sent by any other method, 

to any other address or individual, or 

received after the end of the comment 

period. Comments, including all 

attachments, must not exceed a 25- 

megabyte file size. All comments 

received are a part of the public record 

and will generally be posted online at 

https://www.fisheries.noaa.gov/ 

national/marine-mammal-protection/ 

incidental-take-authorizationsconstruction-activities without change. 

All personal identifying information 

(e.g., name, address) voluntarily 

submitted by the commenter may be 

publicly accessible. Do not submit 

confidential business information or 

otherwise sensitive or protected 

information. 

FOR FURTHER INFORMATION CONTACT: 

Alyssa Clevenstine, Office of Protected 

Resources, NMFS, (301) 427–8401. 

SUPPLEMENTARY INFORMATION: 

Background 

The MMPA prohibits the ‘‘take’’ of 

marine mammals, with certain 

exceptions. Sections 101(a)(5)(A) and 

(D) of the MMPA (16 U.S.C. 1361 et 

seq.) direct the Secretary of Commerce 

(as delegated to NMFS) to allow, upon 

request, the incidental, but not 

intentional, taking of small numbers of 

marine mammals by U.S. citizens who 

engage in a specified activity (other than 

commercial fishing) within a specified 

geographical region if certain findings 

are made and either regulations are 

proposed or, if the taking is limited to 

harassment, a notice of a proposed IHA 

is provided to the public for review. 

Authorization for incidental takings 

shall be granted if NMFS finds that the 

taking will have a negligible impact on 

the species or stock(s) and will not have 

an unmitigable adverse impact on the 

availability of the species or stock(s) for 

taking for subsistence uses (where 

relevant). Further, NMFS must prescribe 

the permissible methods of taking and 

other ‘‘means of effecting the least 

practicable adverse impact’’ on the 

affected species or stocks and their 

habitat, paying particular attention to 

rookeries, mating grounds, and areas of 

similar significance, and on the 

availability of the species or stocks for 

taking for certain subsistence uses 

(referred to in shorthand as 

‘‘mitigation’’); and requirements 

pertaining to the mitigation, monitoring 

and reporting of the takings are set forth. 

The definitions of all applicable MMPA 

statutory terms cited above are included 

in the relevant sections below. 

National Environmental Policy Act 

To comply with the National 

Environmental Policy Act of 1969 

(NEPA; 42 U.S.C. 4321 et seq.) and 

NOAA Administrative Order (NAO) 

216–6A, NMFS must review our 

proposed action (i.e., the issuance of an 

IHA) with respect to potential impacts 

on the human environment. 

This action is consistent with 

categories of activities identified in 

Categorical Exclusion B4 (IHAs with no 

anticipated serious injury or mortality) 

of the Companion Manual for NAO 216– 

6A, which do not individually or 

cumulatively have the potential for 

significant impacts on the quality of the 

human environment and for which we 

have not identified any extraordinary 

circumstances that would preclude this 

categorical exclusion. Accordingly, 

NMFS has preliminarily determined 

that the issuance of the proposed IHA 

qualifies to be categorically excluded 

from further NEPA review. 

We will review all comments 

submitted in response to this notice 

prior to concluding our NEPA process 

or making a final decision on the IHA 

request. 

Summary of Request 

On May 16, 2023, NMFS received a 

request from the City of Oceanside for 

an IHA to take marine mammals 

incidental to construction activities 

associated with fishing pier and nonmotorized vessel improvement in 

Oceanside Harbor, Oceanside, CA. 

Following NMFS’ review of the 

application, the City of Oceanside 

submitted revised versions on July 18 

and October 17, 2023. The application 

was deemed adequate and complete on 

November 2, 2023. The City of 

Oceanside’s request is for take of seven 

species of marine mammals by Level B 

harassment only. Neither the City of 

Oceanside nor NMFS expect serious 

injury or mortality to result from this 

activity and, therefore, an IHA is 

appropriate. 

Description of Proposed Activity 

Overview 

The City of Oceanside proposes to 

remove and replace the existing public 

fishing pier and non-motorized vessel 

launch in Oceanside Harbor, Oceanside, 


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83082 Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 

CA. The purpose of this project is to 

completely replace the pier and launch 

dock with the goals of making the pier 

larger, bringing the pier to current code 

standards, and relocating the launch 

dock to improve accessibility. The 

existing pier is past its design service 

life and has inadequate load-bearing 

capabilities. The applicant intends to 

use vibratory extraction to remove four 

16-inch octagonal concrete support 

piles; vibratory driving to install up to 

18 18-inch round plastic-coated steel 

piles to within 0.61–1.52 meters (m; 2– 

5 feet (ft)) of required depth; and, 

potentially, impact driving to complete 

pile installation depending on observed 

soil resistance. While not expected to be 

required based on site geology, 18 10- 

inch steel piles may be used as 

temporary guide piles to aid in the 

installation of the larger 18-inch 

structural piles. 

A maximum of 6 non-consecutive 

days of piling activities is proposed to 

occur during the course of construction 

(5–6 months) from March 2024 through 

February 2025. The proposed project 

footprint is approximately 0.0081 square 

kilometers (km2; 0.0031 square miles 

(mi2)) with water depths ranging from 

approximately ¥6 m (¥20 ft) below 

mean lower low water (MLLW) and 2.4 

m (7.8 ft) above MLLW. 

Dates and Duration 

This IHA would be effective from 

March 1, 2024, until February 28, 2025. 

The project is anticipated to occur over 

a period of 183 days (5–6 months) from 

March 1, 2024, through February 28, 

2025 (excluding work from April 1 

through August 31, 2024, to account for 

the breeding and nesting season of the 

Endangered Species Act (ESA)-listed 

California least tern (Sternula 

antillarum browni)), and in-water pile 

activity is anticipated to occur for 6 

non-consecutive days during that time. 

The City of Oceanside plans to conduct 

piling activities during daylight hours, 

generally limited to between 45 minutes 

post-sunrise and 45 minutes pre-sunset. 

Pile removal and installation activities 

may take place concurrently, where 

multiple piles are extracted or installed 

during a day, but not coincidentally. 

Pile extraction is anticipated to take 1 

day and pile installation is anticipated 

to take 5 days. 

Specific Geographic Region 

This project would be located at the 

existing Oceanside Harbor Fishing Pier 

in Oceanside, CA (Figure 1), with 

depths ranging from approximately 6 m 

below to 2.4 m above MLLW. 

BILLING CODE 3510–22–P 


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BILLING CODE 3510–22–C 

Activity 

Detailed Description of the Specified 

Vibratory extraction of four existing 

16-inch octagonal concrete support piles potential for an additional 18 10-inch 

plastic-coated steel pipe piles, with the 

installation of up to 18 18-inch round 

would occur in 1 day. Vibratory 


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CJNewPier 

•• - -. Elli!l1ing P-ier ..... c:::J Pmposed Project Footprint 

,"'\.,./ 2ft8alhymelricConlour 

Figure 1 - Map of Proposed Project Area in Oceanside Harbor, California 
83084 Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 

temporary steel guide piles, would 

occur over 5 days (table 1). If 10-inch 

steel guide piles are needed, they will 

be installed and extracted via vibratory 

hammer within the same timeframe as 

the permanent piles. New 18-inch steel 

piles will be installed with a vibratory 

hammer until they are within 0.61–1.52 

m of the required depth, at which point 

the remaining driving will be done with 

an impact hammer depending on 

observed sediment resistance. 

Temporary 10-inch guide piles would 

only be installed to aid in installation of 

structural 18-inch piles if hard 

sediments are encountered that will 

deflect pile positioning. All activities 

may occur with or without highpressure water jetting. 

TABLE 1—PILE EXTRACTION AND INSTALLATION ACTIVITIES

Pile activity Method Pile size (inch), 

material Piles per day 

Duration of 

activity 

(days) 

Duration of 

vibratory 

activity 

per pile 

(minutes) 

Estimated 

blows of impact 

driving per pile 

(strikes) 

Extraction ................... Vibratory .................... 16, concrete .............. 4 1 25 N/A 

Installation .................. Vibratory .................... 18, steel ..................... 4 * 5 25 N/A 

Installation .................. Impact ........................ 18, steel ..................... 4 * 5 N/A 300 

Installation .................. Vibratory .................... 10, steel ..................... 4 N/A 10 N/A 

Note: Impact pile installation will be used for driving piles 0.61–1.52 m to final depth, depending on observed sediment resistance. 

* Vibratory and impact installation of 18-inch steel piles would occur in the same 5 days. 

Other pile removal methods, 

including removing piles via highpressure water jet may also occur, but 

no take of marine mammals is 

anticipated to occur incidental to this 

portion of the project and these 

activities will not be discussed further. 

Proposed mitigation, monitoring, and 

reporting measures are described in 

detail later in this document (please see 

Proposed Mitigation and Proposed 

Monitoring and Reporting). 

Description of Marine Mammals in the 

Area of Specified Activities 

Sections 3 and 4 of the application 

summarize available information 

regarding status and trends, distribution 

and habitat preferences, and behavior 

and life history of the potentially 

affected species. NMFS fully considered 

all of this information and we refer the 

reader to these descriptions instead of 

reprinting the information. Additional 

information regarding population trends 

and threats may be found in NMFS’ 

Stock Assessment Reports (SAR; https:// 

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/marinemammal-stock-assessments) and more 

general information about these species 

(e.g., physical and behavioral 

descriptions) may be found on NMFS’ 

website (https://

www.fisheries.noaa.gov/find-species). 

Table 2 lists all species or stocks for 

which take is expected and proposed to 

be authorized for this activity, and 

summarizes information related to the 

population or stock, including 

regulatory status under the MMPA and 

ESA and potential biological removal 

(PBR), where known. PBR is defined by 

the MMPA as the maximum number of 

animals, not including natural 

mortalities, that may be removed from a 

marine mammal stock while allowing 

that stock to reach or maintain its 

optimum sustainable population (as 

described in NMFS’ SARs). While no 

serious injury or mortality is anticipated 

or proposed to be authorized here, PBR 

and annual serious injury and mortality 

from anthropogenic sources are 

included here as gross indicators of the 

status of the species or stocks and other 

threats. 

Marine mammal abundance estimates 

presented in this document represent 

the total number of individuals that 

make up a given stock or the total 

number estimated within a particular 

study or survey area. NMFS’ stock 

abundance estimates for most species 

represent the total estimate of 

individuals within the geographic area, 

if known, that comprises that stock. For 

some species, this geographic area may 

extend beyond U.S. waters. All managed 

stocks in this region are assessed in 

NMFS’ U.S. Pacific SARs. All values 

presented in table 2 are the most recent 

available at the time of publication 

(including from the final 2022 SARs) 

and are available online at: https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/marinemammal-stock-assessments. 

TABLE 2—MARINE MAMMAL SPECIES LIKELY IMPACTED BY THE SPECIFIED ACTIVITIES

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

strategic 

(Y/N) 2

Stock abundance 

(CV, Nmin, most recent 

abundance survey) 3

PBR Annual 

M/SI 4

Odontoceti (toothed whales, dolphins, and porpoises) 

Family Delphinidae: 

Bottlenose dolphin .......... Tursiops truncatus ................ California Coastal ................. -/-; N 453 (0.06, 346, 2011) .......... 2.7 ≥2 

Long-beaked common 

dolphin.

Delphinus delphis capensis California .............................. -/-; N 83,379 (0.216, 69,636, 2018) 668 ≥29.7 

Short-beaked common 

dolphin.

Delphinus delphis delphis .... California/Oregon/Washington.-/-; N 1,056,308 (0.21, 888,971, 

2018).

8,889 ≥30.5 

Pacific white-sided dolphin.Lagenorhynchus obliquidens California .............................. -/-; N 34,999 (0.222, 29,090, 2018) 279 7 

Order Carnivora—Pinnipedia 

Family Otariidae (eared seals 

and sea lions): 


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TABLE 2—MARINE MAMMAL SPECIES LIKELY IMPACTED BY THE SPECIFIED ACTIVITIES—Continued 

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

strategic 

(Y/N) 2

Stock abundance 

(CV, Nmin, most recent 

abundance survey) 3

PBR Annual 

M/SI 4

California sea lion .......... Zalophus californianus ......... U.S. ...................................... -/-; N 257,606 (N/A, 233,515, 

2015).

14,011 >321 

Family Phocidae (earless 

seals): 

Harbor seal ..................... Phoca vitulina richardii ......... California .............................. -/-; N 30,968 (0.157, 27,348, 2012) 1,641 42.8 

Northern elephant seal ... Mirounga angustirostris ........ California Breeding ............... -/-; N 187,386 (N/A, 85,369, 2013) 5,122 13.7 

1 Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy’s Committee on Taxonomy 

(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)). 2ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be 

declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA 

as depleted and as a strategic stock. 3 NMFS marine mammal stock assessment reports online at: https://www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of 

stock abundance. 4These values, found in NMFS’s SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases. 

As indicated above, all seven species 

in table 2 temporally and spatially cooccur with the activity to the degree that 

take is reasonably likely to occur. Based 

on previous marine mammal monitoring 

events near the mouth of Oceanside 

Harbor (Merkel and Associates, Inc., 

2022; Merkel and Associates, Inc., 

2023), other marine mammals rarely 

occur within Oceanside Harbor and any 

occurrence in the project area would be 

very rare. While Risso’s dolphins 

(Grampus griseus) and gray whales 

(Eschrichtius robustus) have been 

sighted outside of the harbor and in 

coastal waters, these species’ general 

spatial occurrence is such that take is 

not expected to occur as they typically 

occur more offshore, and they are not 

discussed further beyond the 

explanation provided here. 

Bottlenose Dolphin 

Bottlenose dolphins (California 

coastal stock) occur in coastal waters 

within 1 km of shore, primarily between 

Point Conception, CA, and San Quintin, 

Mexico (Hansen, 1990, Carretta et al., 

1998). California coastal bottlenose 

dolphins show little site fidelity and 

likely move within their home range in 

response to patchy concentrations of 

nearshore prey (Defran and Weller, 

1999, Bearzi et al., 2009). 

Oceanographic events may influence the 

distribution and residency patterns of 

dolphins (Hansen and Defran, 1990, 

Wells et al., 1990). In southern 

California, coastal bottlenose dolphins 

are typically found within 250 m of the 

shoreline (Hansen and Defran, 1993). 

Bottlenose dolphin sightings are not 

common in Oceanside Harbor but do 

occur, typically within the outer surge 

basin of the harbor and, rarely, within 

the inner harbor. 

Common Dolphin (Long-Beaked and 

Short-Beaked) 

Short-beaked common dolphins 

(California/Oregon/Washington stock) 

are the most abundant cetacean off of 

California and are widely distributed 

between the coast and approximately 

556 km offshore. In contrast, longbeaked common dolphins (California 

stock) are considered a nearshore 

species and generally occur within 92.6 

km of shore. Both stocks may shift their 

distributions seasonally and annually in 

response to oceanographic conditions 

and prey availability (Carretta et al., 

2023). Long-beaked common dolphins 

tend to prefer shallower, warmer waters 

as compared to the short-beaked 

common dolphin (Perrin, 2009), yet 

both stocks appear to be more abundant 

in coastal waters during warm-water 

months (Bearzi, 2005). 

While there is no occurrence data for 

common dolphin in Oceanside Harbor, 

they are rare visitors to the northern 

portion of San Diego Bay and could be 

expected to be rare visitors within the 

outer portion of Oceanside Harbor. 

Pacific White-Sided Dolphin 

Pacific white-sided dolphins 

(California stock) are endemic to 

temperate waters of the North Pacific 

Ocean, and are the most abundant 

pelagic species of dolphin in the region 

(Carretta et al., 2023). Off the U.S. West 

Coast, Pacific white-sided dolphins 

occur primarily in shelf and slope 

waters. Sighting patterns from aerial and 

shipboard surveys conducted in 

California, Oregon, and Washington 

suggest seasonal north-south 

movements, with animals found 

primarily off California during colder 

water months and shifting northward 

into Oregon and Washington as water 

temperatures increase in late spring and 

summer (Green et al., 1992, Green et al., 

1993, Forney and Barlow, 1998, Carretta 

et al., 2023). Pacific white-sided 

dolphins are highly social and 

commonly occur in groups of less than 

a hundred, although groups of several 

thousands of individuals have been 

observed. They often associate with 

Risso’s dolphins and short-beaked 

common dolphins, and occasionally 

feed in association with California sea 

lions and mixed species aggregations of 

seabirds. 

No data of Pacific white-sided 

dolphin occurrence within Oceanside 

Harbor exists but, as they do occur in 

the waters of southern California, they 

could enter the outer portion of 

Oceanside Harbor. 

California Sea Lion 

California sea lions occur from 

Vancouver Island, British Columbia, to 

the southern tip of Baja California, 

Mexico. Habitat use and distribution 

varies with sex and reproductive stage, 

and sea lions breed on the offshore 

islands of southern California, western 

Baja California, and the Gulf of 

California from May through July (Heath 

and Perrin, 2009, Lowry et al., 2017). 

Adult males may haul out on land to 

breed and defend territory from midMay through late July. Adult males and 

females are known to haul out more 

often during warm-water months. 

California sea lions are commonly 

seen in the proposed project area and 

generally in and around Oceanside 

Harbor on a pinniped haulout float, 

buoys, rocks, and other structures 

throughout the harbor (Merkel and 

Associates, Inc., 2023). Beyond these 

structures, there are no known natural 

haulout locations near the proposed 

action area. Abundance in the proposed 

project area varies substantially through 


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time, with variability also being driven 

by food availability and breeding season 

movements (pers. comm. Oceanside 

Harbor Department). California sea lions 

in Oceanside Harbor are typically 

concentrated around the pinniped float 

approximately 21 m north of the end of 

the existing fishing pier in the proposed 

project area. This structure was installed 

several years ago to attract sea lions 

away from docks and boats (see Figure 

2–1 in application). The Harbor 

Department noted that the pinniped 

float varies from being completely full 

(approximately 100 animals or more) to 

completely empty. Prior to in-water 

activity, the pinniped float would be 

relocated by the Oceanside Harbor 

Department when no sea lions or other 

marine mammals are present to 

minimize attraction of sea lions to the 

proposed work area during 

construction. 

California sea lions experienced an 

Unusual Mortality Event (UME), not 

correlated to an El Nin ̃o event, from 

2013–2017 (Carretta et al., 2023). Pup 

and juvenile age classes experienced 

high mortality during this time, likely 

attributed to a lack of prey availability, 

specifically Pacific sardines (Sardinops 

sagax). California sea lions are also 

susceptible to the algal neurotoxin 

domoic acid (Carretta et al., 2023), 

which is expected to cause future 

mortalities among California sea lions 

due to the prevalence of harmful algal 

blooms within their habitat, as 

evidenced by recent stranding events 

along parts of the Southern California 

coast in summer 2023. 

Harbor Seal 

Harbor seals are distributed from Baja 

California, Mexico, to the eastern 

Aleutian Islands of Alaska (Harvey and 

Goley, 2011). Harbor seals do not make 

extensive pelagic migrations but may 

travel hundreds of kilometers to find 

food or suitable breeding areas (Harvey 

and Goley, 2011, Carretta et al., 2023). 

Seals primarily haul out on remote 

mainland and island beaches, reefs, and 

estuary areas. At haulout sites, they 

congregate to rest, socialize, breed, and 

molt. In California, there are 

approximately 500 haulout sites along 

the mainland and on offshore islands, 

including intertidal sandbars, rocky 

shores, and beaches (Hanan, 1996, 

Lowry et al., 2008). 

Harbor seals are present within 

Oceanside Harbor, primarily in the 

outer surge basin and not typically 

within the inner harbor (Merkel and 

Associates, Inc., 2023). Harbor seals may 

haul out on the pinniped float, rocks, 

buoys, or other structures within the 

harbor. 

Northern Elephant Seal 

Northern elephant seals breed and 

give birth in California and Baja 

California, mainly on offshore islands 

during the months of December through 

March (Stewart and Huber, 1993, 

Stewart et al., 1994, Carretta et al., 

2023). Molting season takes place from 

March to August. In between the spring/ 

summer molting season and winter 

breeding season, northern elephant seals 

migrate north, exhibiting spatial 

segregation in foraging areas in the Gulf 

of Alaska, western Aleutian Islands, and 

central North Pacific Ocean to feeding 

grounds (Carretta et al., 2023). Northern 

elephant seal populations in the United 

States and Mexico have recovered after 

being hunted to near extinction (Stewart 

et al., 1994) and undergoing a severe 

population bottleneck, leading to a loss 

of genetic diversity, that resulted in the 

population being reduced to an 

estimated 10–30 individuals (Hoelzel et 

al., 2002, Carretta et al., 2023). There are 

two distinct populations of northern 

elephant seals, including a breeding 

population in Baja California, Mexico, 

and a breeding population on U.S. 

islands off of California. Northern 

elephant seals in the region could be 

from either population (Carretta et al., 

2023). 

Northern elephant seals rarely occur 

in the Southern California Bight and are 

not expected to occur in Oceanside 

Harbor. However, given the species has 

been sighted along the southern 

California coast in recent years, 

potentially due to the continuing longterm increase in the population of 

northern elephant seals (Lowry et al., 

2020), there is a possibility of 

occurrence in the project area. 

Marine Mammal Hearing 

Hearing is the most important sensory 

modality for marine mammals 

underwater, and exposure to 

anthropogenic sound can have 

deleterious effects. To appropriately 

assess the potential effects of exposure 

to sound, it is necessary to understand 

the frequency ranges marine mammals 

are able to hear. Not all marine mammal 

species have equal hearing capabilities 

(e.g., Richardson et al., 1995, Wartzok 

and Ketten, 1999, Au and Hastings, 

2008). To reflect this, Southall et al. 

(2007, 2019) recommended that marine 

mammals be divided into hearing 

groups based on directly measured 

(behavioral or auditory evoked potential 

techniques) or estimated hearing ranges 

(behavioral response data, anatomical 

modeling, etc.). Note that no direct 

measurements of hearing ability have 

been successfully completed for 

mysticetes (i.e., low-frequency 

cetaceans). Subsequently, NMFS (2018) 

described generalized hearing ranges for 

these marine mammal hearing groups. 

Generalized hearing ranges were chosen 

based on the approximately 65 decibel 

(dB) threshold from the normalized 

composite audiograms, with the 

exception for lower limits for lowfrequency cetaceans where the lower 

bound was deemed to be biologically 

implausible and the lower bound from 

Southall et al. (2007) was retained. 

Marine mammal hearing groups and 

their associated hearing ranges are 

provided in table 3. 

TABLE 3—MARINE MAMMAL HEARING GROUPS

[NMFS, 2018] 

Hearing group Generalized hearing range * 

Low-frequency (LF) cetaceans (baleen whales) ................................................................................................ 7 Hz to 35 kHz. 

Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) ..................... 150 Hz to 160 kHz. 

High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, Cephalorhynchid, Lagenorhynchus 

cruciger & L. australis).

275 Hz to 160 kHz. 

Phocid pinnipeds (PW) (underwater) (true seals) ............................................................................................. 50 Hz to 86 kHz. 

Otariid pinnipeds (OW) (underwater) (sea lions and fur seals) ......................................................................... 60 Hz to 39 kHz. 

* Represents the generalized hearing range for the entire group as a composite (i.e., all species within the group), where individual species’ 

hearing ranges are typically not as broad. Generalized hearing range chosen based on ∼65 dB threshold from normalized composite audiogram, 

with the exception for lower limits for LF cetaceans (Southall et al., 2007) and PW pinniped (approximation). 


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The pinniped functional hearing 

group was modified from Southall et al. 

(2007) on the basis of data indicating 

that phocid species have consistently 

demonstrated an extended frequency 

range of hearing compared to otariids, 

especially in the higher frequency range 

(Hemila ̈ et al., 2006, Kastelein et al., 

2009, Reichmuth et al., 2013). 

For more detail concerning these 

groups and associated frequency ranges, 

please see NMFS (2018) for a review of 

available information. 

Potential Effects of Specified Activities 

on Marine Mammals and Their Habitat 

This section provides a discussion of 

the ways in which components of the 

specified activity may impact marine 

mammals and their habitat. The 

Estimated Take of Marine Mammals 

section later in this document includes 

a quantitative analysis of the number of 

individuals that are expected to be taken 

by this activity. The Negligible Impact 

Analysis and Determination section 

considers the content of this section, the 

Estimated Take of Marine Mammals 

section, and the Proposed Mitigation 

section, to draw conclusions regarding 

the likely impacts of these activities on 

the reproductive success or survivorship 

of individuals and whether those 

impacts are reasonably expected to, or 

reasonably likely to, adversely affect the 

species or stock through effects on 

annual rates of recruitment or survival. 

Acoustic effects on marine mammals 

during the specified activities can occur 

from impact pile driving and vibratory 

pile driving and removal. The effects of 

underwater noise from the City of 

Oceanside’s proposed activities have the 

potential to result in Level B harassment 

of marine mammals in the project area. 

Description of Sound Sources 

The marine soundscape is comprised 

of both ambient and anthropogenic 

sounds. Ambient sound is defined as 

the all-encompassing sound in a given 

place and is usually a composite of 

sound from many sources both near and 

far (ANSI, 1995). The sound level of an 

area is defined by the total acoustical 

energy being generated by known and 

unknown sources. These sources may 

include physical (e.g., waves, wind, 

precipitation, earthquakes, ice, 

atmospheric sound), biological (e.g., 

sounds produced by marine mammals, 

fish, and invertebrates), and 

anthropogenic sound (e.g., vessels, 

dredging, aircraft, construction). 

The sum of the various natural and 

anthropogenic sound sources at any 

given location and time—which 

comprise ‘‘ambient’’ or ‘‘background’’ 

sound—depends not only on the source 

levels (as determined by current 

weather conditions and levels of 

biological and shipping activity) but 

also on the ability of sound to propagate 

through the environment. In turn, sound 

propagation is dependent on the 

spatially and temporally varying 

properties of the water column and sea 

floor, and is frequency-dependent. As a 

result of the dependence on a large 

number of varying factors, ambient 

sound levels can be expected to vary 

widely over both coarse and fine spatial 

and temporal scales. Sound levels at a 

given frequency and location can vary 

by 10–20 dB from day to day 

(Richardson et al., 1995). The result is 

that, depending on the source type and 

its intensity, sound from the specified 

activities may be a negligible addition to 

the local environment or could form a 

distinctive signal that may affect marine 

mammals. 

In-water construction activities 

associated with the proposed project 

would include vibratory pile extraction 

and vibratory pile installation, and, 

potentially, impact pile installation. The 

sounds produced by these activities fall 

into one of two general sound types: 

impulsive and non-impulsive. 

Impulsive sounds (e.g., explosions, 

sonic booms, impact pile driving) are 

typically transient, brief (less than 1 

second), broadband, and consist of high 

peak sound pressure with rapid rise 

time and rapid decay (ANSI, 1986, 

NIOSH, 1998, NMFS, 2018). Nonimpulsive sounds (e.g., machinery 

operations such as drilling or dredging, 

vibratory pile driving, underwater 

chainsaws, and active sonar systems) 

can be broadband, narrowband, or tonal, 

brief or prolonged (continuous or 

intermittent), and typically do not have 

the high peak sound pressure with raid 

rise/decay time that impulsive sounds 

do (ANSI, 1995, NIOSH, 1998, NMFS, 

2018). The distinction between these 

two sound types is important because 

they have differing potential to cause 

physical effects, particularly with regard 

to hearing (e.g., Ward, 1997). 

Two types of hammers would be used 

on this project, vibratory and, if 

necessary, impact. Vibratory hammers 

install piles by vibrating them and 

allowing the weight of the hammer to 

push them into the sediment. Vibratory 

hammers produce non-impulsive, 

continuous sounds. Vibratory 

hammering generally produces sound 

pressure levels (SPLs) 10–20 dB lower 

than impact pile driving of the samesized pile (Oestman et al., 2009). Rise 

time is slower, reducing the probability 

and severity of injury, and sound energy 

is distributed over a greater amount of 

time (Nedwell and Edwards, 2002, 

Carlson et al., 2005). Impact hammers 

operate by repeatedly dropping and/or 

pushing a heavy piston onto a pile to 

drive the pile into the substrate. Sound 

generated by impact hammers is 

considered impulsive. 

The likely or possible impacts of the 

City of Oceanside’s proposed activities 

on marine mammals could be generated 

from both non-acoustic and acoustic 

stressors. Potential non-acoustic 

stressors include the physical presence 

of the equipment, vessels, and 

personnel; however, we expect that any 

animals that approach the project site 

close enough to be harassed due to the 

presence of equipment or personnel 

would be within the Level B harassment 

zones from pile removal or driving and 

would already be subject to harassment 

from the in-water activities. Therefore, 

any impacts to marine mammals are 

expected to primarily be acoustic in 

nature. Acoustic stressors are generated 

by heavy equipment operation during 

pile driving activities (i.e., impact and 

vibratory pile driving and removal). 

Acoustic Impacts 

The introduction of anthropogenic 

noise into the aquatic environment from 

pile driving equipment is the primary 

means by which marine mammals may 

be harassed from the City of Oceanside’s 

specified activities. In general, animals 

exposed to natural or anthropogenic 

sound may experience physical and 

psychological effects, ranging in 

magnitude from none to severe 

(Southall et al., 2007). Generally, 

exposure to pile driving and removal 

and other construction noise has the 

potential to result in auditory threshold 

shifts (TS) and behavioral reactions 

(e.g., avoidance, temporary cessation of 

foraging and vocalizing, changes in dive 

behavior). Exposure to anthropogenic 

noise can also lead to non-observable 

physiological responses, such as an 

increase in stress hormones. Additional 

noise in a marine mammal’s habitat can 

mask acoustic cues used by marine 

mammals to carry out daily functions, 

such as communication and predator 

and prey detection. The effects of pile 

driving and construction noise on 

marine mammals are dependent on 

several factors including, but not 

limited to, sound type (e.g., impulsive 

vs. non-impulsive), the species, age and 

sex class (e.g., adult male vs. mother 

with calf), duration of exposure, the 

distance between the pile and the 

animal, received levels, behavior at time 

of exposure, and previous history with 

exposure (Wartzok et al., 2004, Southall 

et al., 2007). Here we discuss physical 

auditory effects (threshold shifts) 


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followed by behavioral effects and 

potential impacts on habitat. 

NMFS defines a noise-induced TS as 

a change, usually an increase, in the 

threshold of audibility at a specified 

frequency or portion of an individual’s 

hearing range above a previously 

established reference level (NMFS, 

2018). The amount of TS is customarily 

expressed in dB and TS can be 

permanent or temporary. As described 

in NMFS (2018), there are numerous 

factors to consider when examining the 

consequence of TS, including, but not 

limited to, the signal temporal pattern 

(e.g., impulsive or non-impulsive), 

likelihood an individual would be 

exposed for a long enough duration or 

to a high enough level to induce a TS, 

the magnitude of the TS, time to 

recovery (seconds to minutes or hours to 

days), the frequency range of the 

exposure (i.e., spectral content), the 

hearing and vocalization frequency 

range of the exposed species relative to 

the signal’s frequency spectrum (i.e., 

how animal uses sound within the 

frequency band of the signal) (Kastelein 

et al., 2014b), and the overlap between 

the animal and the source (e.g., spatial, 

temporal, and spectral). 

Permanent Threshold Shift (PTS)— 

NMFS defines PTS as a permanent, 

irreversible increase in the threshold of 

audibility at a specified frequency or 

portion of an individual’s hearing range 

above a previously established reference 

level (NMFS, 2018). Available data from 

humans and other terrestrial mammals 

indicate that a 40 dB TS approximates 

PTS onset (see Ward et al., 1958, Ward 

et al., 1959, Ward, 1960, Kryter et al., 

1966, Miller, 1974, Ahroon et al., 1996, 

Henderson et al., 2008). PTS levels for 

marine mammals are estimates because 

there are limited empirical data 

measuring PTS in marine mammals 

(e.g., Kastak et al., 2008), largely due to 

the fact that, for various ethical reasons, 

experiments involving anthropogenic 

noise exposure at levels inducing PTS 

are not typically pursued or authorized 

(NMFS, 2018). 

Temporary Threshold Shift (TTS)— 

TTS is a temporary, reversible increase 

in the threshold of audibility at a 

specified frequency or portion of an 

individual’s hearing range above a 

previously established reference level 

(NMFS, 2018). Based on data from 

cetacean TTS measurements (see 

Southall et al., 2007), a TTS of 6 dB is 

considered the minimum TS clearly 

larger than any day-to-day or session-tosession variation in a subject’s normal 

hearing ability (Schlundt et al., 2000, 

Finneran et al., 2000, FInneran et al., 

2002). As described in Finneran (2016), 

marine mammal studies have shown the 

amount of TTS increases with 

cumulative sound exposure level 

(SELcum) in an accelerating fashion: At 

low exposures with lower SELcum, the 

amount of TTS is typically small and 

the growth curves have shallow slopes. 

At exposures with higher SELcum, the 

growth curves become steeper and 

approach linear relationships with the 

noise SEL. 

Depending on the degree (elevation of 

threshold in dB), duration (i.e., recovery 

time), and frequency range of TTS, and 

the context in which it is experienced, 

TTS can have effects on marine 

mammals ranging from discountable to 

serious (similar to those discussed in 

auditory Masking, below). For example, 

a marine mammal may be able to readily 

compensate for a brief, relatively small 

amount of TTS in a non-critical 

frequency range that takes place during 

a time when the animal is traveling 

through the open ocean, where ambient 

noise is lower and there are not as many 

competing sounds present. 

Alternatively, a larger amount and 

longer duration of TTS sustained during 

time when communication is critical for 

successful mother/calf interactions 

could have more serious impacts. We 

note that reduced hearing sensitivity as 

a simple function of aging has been 

observed in marine mammals, as well as 

humans and other taxa (Southall et al., 

2007), so we can infer that strategies 

exist for coping with this condition to 

some degree, though likely not without 

cost. 

Currently, TTS data only exist for four 

species of cetaceans (bottlenose 

dolphin, beluga whale (Delphinapterus 

leucas), harbor porpoise (Phocoena 

phocoena), Yangtze finless porpoise 

(Neophocoena asiaeorientalis)) and five 

species of pinnipeds exposed to a 

limited number of sound sources (i.e., 

tones and octave-band noise) in 

laboratory settings (Finneran, 2015). 

TTS was not observed in trained spotted 

seals (Phoca largha) and ringed seals 

(Pusa hispida) exposed to impulsive 

noise at levels matching previous 

predictions of TTS onset (Reichmuth et 

al., 2016). In general, harbor seals and 

harbor porpoises have a lower TTS 

onset than other measured pinniped or 

cetacean species (Finneran, 2015). At 

low frequencies, onset-TTS exposure 

levels are higher compared to those in 

the region of best sensitivity (i.e., a low 

frequency noise would need to be 

louder to cause TTS onset when TTS 

exposure level is higher), as shown for 

harbor porpoises and harbor seals 

(Kastelein et al., 2019b, Kastelein et al., 

2019a, Kastelein et al., 2020a, Kastelein 

et al., 2020b). In addition, TTS can 

accumulate across multiple exposures 

but the resulting TTS will be less than 

the TTS from a single, continuous 

exposure with the same SEL (Mooney et 

al., 2009, Finneran et al., 2010, 

Kastelein et al., 2014a, Kastelein et al., 

2015). This means that TTS predictions 

based on the total SELcum will 

overestimate the amount of TTS from 

intermittent exposures such as sonars 

and impulsive sources. 

The potential for TTS from impact 

pile driving exists. After exposure to 

playbacks of impact pile driving sounds 

(rate 2,760 strikes/hour) in captivity, 

mean TTS increased from 0 dB after a 

15 minute exposure to 5 dB after a 360 

minute exposure; recovery occurred 

within 60 minutes (Kastelein et al., 

2016). Additionally, the existing marine 

mammal TTS data come from a limited 

number of individuals within these 

species. No data are available on noiseinduced hearing loss for mysticetes. 

Nonetheless, what we considered is the 

best available science. For summaries of 

data on TTS in marine mammals or for 

further discussion of TTS onset 

thresholds, please see Southall et al. 

(2007), Southall et al. (2019), Finneran 

and Jenkins (2012), Finneran (2015), 

and table 5 in NMFS (2018). 

Proposed activities for this project 

include vibratory pile driving and 

vibratory pile removal and, potentially, 

impact pile driving. There would likely 

be pauses in activities producing the 

sound during each day and, given these 

pauses and the fact that many marine 

mammals would likely be moving 

through the project areas and not 

remaining for extended periods of time, 

the potential for TS declines. 

Behavioral Harassment—Exposure to 

noise from pile driving and removal also 

has the potential to behaviorally disturb 

marine mammals. Available studies 

show wide variation in response to 

underwater sound; therefore, it is 

difficult to predict specifically how any 

given sound in a particular instance 

might affect marine mammals 

perceiving the signal. If a marine 

mammal does react briefly to an 

underwater sound by changing its 

behavior or moving a small distance, the 

impacts of the change are unlikely to be 

significant to the individual, let alone 

the stock or population. However, if a 

sound source displaces marine 

mammals from an important feeding or 

breeding area for a prolonged period, 

impacts on individuals and populations 

could be significant (e.g., Council, 2005, 

Lusseau and Bejder, 2007, Weilgart, 

2007b). 

Disturbance may result in changing 

durations of surfacing and dives, 

number of blows per surfacing, or 

moving direction and/or speed; 


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reduced/increased vocal activities; 

changing/cessation of certain behavioral 

activities (such as socializing or 

feeding); visible startle response or 

aggressive behavior (such as tail/fluke 

slapping or jaw clapping); or avoidance 

of areas where sound sources are 

located. Pinnipeds may increase their 

haulout time, possibly to avoid in-water 

disturbance (Thorson and Reyff, 2006). 

Behavioral responses to sound are 

highly variable and context-specific and 

any reactions depend on numerous 

intrinsic and extrinsic factors (e.g., 

species, state of maturity, experience, 

current activity, reproductive state, 

auditory sensitivity, time of day), as 

well as the interplay between factors 

(e.g., Richardson et al., 1995, Wartzok et 

al., 2004, Southall et al., 2007, Weilgart, 

2007a, Archer et al., 2010, Southall et 

al., 2021). Behavioral reactions can vary 

not only among individuals but also 

within an individual depending on 

previous experience with a sound 

source, context, and numerous other 

factors (Ellison et al., 2012), and can 

vary depending on characteristics 

associated with the sound source (e.g., 

whether it is moving or stationary, 

number of sources, distance from the 

source). In general, pinnipeds seem 

more tolerant of, or at least habituate 

more quickly to, potentially disturbing 

underwater sound than do cetaceans, 

and generally seem to be less responsive 

to exposure to industrial sound than 

most cetaceans. Please see Appendices 

B and C of Southall et al. (2007) as well 

as Nowacek et al. (2007), Ellison et al. 

(2012), and Gomez et al. (2016) for a 

review of studies involving marine 

mammal behavioral responses to sound. 

Disruption of feeding behavior can be 

difficult to correlate with anthropogenic 

sound exposure, so it is usually inferred 

by observed displacement from known 

foraging areas, the appearance of 

secondary indicators (e.g., bubble nets 

or sediment plumes), or changes in dive 

behavior. As for other types of 

behavioral response, the frequency, 

duration, and temporal pattern of signal 

presentation, as well as differences in 

species sensitivity, are likely 

contributing factors to differences in 

response in any given circumstance 

(e.g., Croll et al., 2001, Nowacek et al., 

2004, Madsen et al., 2006, Yazvenko et 

al., 2007, Melcon et al., 2012). In 

addition, behavioral state of the animal 

plays a role in the type and severity of 

a behavioral response, such as 

disruption to foraging (e.g., Sivle et al., 

2016, Wensveen et al., 2017). A 

determination of whether foraging 

disruptions incur fitness consequences 

would require information on, or 

estimates of, the energetic requirements 

of the affected individuals and the 

relationship between prey availability, 

foraging effort and success, and the life 

history stage of the animal (Goldbogen 

et al., 2013). 

Stress responses—An animal’s 

perception of a threat may be sufficient 

to trigger stress responses consisting of 

some combination of behavioral 

responses, autonomic nervous system 

responses, neuroendocrine responses, or 

immune responses (e.g., Selye, 1950, 

Moberg, 2000). In many cases, an 

animal’s first and sometimes most 

economical (in terms of energetic costs) 

response is behavioral avoidance of the 

potential stressor. Autonomic nervous 

system responses to stress typically 

involve changes in heart rate, blood 

pressure, and gastrointestinal activity. 

These responses have a relatively short 

duration and may or may not have a 

significant long-term effect on an 

animal’s fitness. 

Neuroendocrine stress responses often 

involve the hypothalamus-pituitaryadrenal system. Virtually all 

neuroendocrine functions that are 

affected by stress—including immune 

competence, reproduction, metabolism, 

and behavior—are regulated by pituitary 

hormones. Stress-induced changes in 

the secretion of pituitary hormones have 

been implicated in failed reproduction, 

altered metabolism, reduced immune 

competence, and behavioral disturbance 

(e.g., Moberg, 1987, Blecha, 2000). 

Increases in the circulation of 

glucocorticoids are also equated with 

stress (Romano et al., 2004). 

The primary distinction between 

stress (which is adaptive and does not 

normally place an animal at risk) and 

‘‘distress’’ is the cost of the response. 

During a stress response, an animal uses 

glycogen stores that can be quickly 

replenished once the stress is alleviated. 

In such circumstances, the cost of the 

stress response would not pose serious 

fitness consequences. However, when 

an animal does not have sufficient 

energy reserves to satisfy the energetic 

costs of a stress response, energy 

resources must be diverted from other 

functions. This state of distress will last 

until the animal replenishes its 

energetic reserves sufficient to restore 

normal function. 

Relationships between these 

physiological mechanisms, animal 

behavior, and the costs of stress 

responses are well-studied through 

controlled experiments for both 

laboratory and free-ranging animals 

(e.g., Holberton et al., 1996, Hood et al., 

1998, Jessop et al., 2003, Krausman et 

al., 2004, Lankford et al., 2005). Stress 

responses due to exposure to 

anthropogenic sounds or other stressors 

and their effects on marine mammals 

have also been reviewed (Fair and 

Becker, 2000, Romano et al., 2002b) 

and, more rarely, studied in wild 

populations (e.g., Romano et al., 2002a). 

For example, Rolland et al. (2012) found 

that noise reduction from reduced 

vessel traffic in the Bay of Fundy was 

associated with decreased stress in 

North Atlantic right whales (Eubalaena 

glacialis). These and other studies lead 

to a reasonable expectation that some 

marine mammals will experience 

physiological stress responses upon 

exposure to acoustic stressors and that 

it is possible that some of these would 

be classified as ‘‘distress.’’ In addition, 

any animal experiencing TTS would 

likely also experience stress responses 

(NRC, 2003), however, distress is an 

unlikely result of the proposed project 

based on observations of marine 

mammals during previous, similar 

projects in the region. 

Masking—Sound can disrupt behavior 

through masking, or interfering with, an 

animal’s ability to detect, recognize, or 

discriminate between acoustic signals of 

interest (e.g., those used for intraspecific 

communication and social interactions, 

prey detection, predator avoidance, 

navigation) (Richardson et al., 1995). 

Masking occurs when the receipt of a 

sound is interfered with by another 

coincident sound at similar frequencies 

and at similar or higher intensity, and 

may occur whether the sound is natural 

(e.g., snapping shrimp, wind, waves, 

precipitation) or anthropogenic (e.g., 

pile driving, shipping, sonar, seismic 

exploration) in origin. The ability of a 

noise source to mask biologically 

important sounds depends on the 

characteristics of both the noise source 

and the signal of interest (e.g., signal-tonoise ratio, temporal variability, 

direction), in relation to each other and 

to an animal’s hearing abilities (e.g., 

sensitivity, frequency range, critical 

ratios, frequency discrimination, 

directional discrimination, age or TTS 

hearing loss), and existing ambient 

noise and propagation conditions. 

Masking of natural sounds can result 

when human activities produce high 

levels of background sound at 

frequencies important to marine 

mammals. Conversely, if the 

background level of underwater sound 

is high (e.g., on a day with strong wind 

and high waves), an anthropogenic 

sound source would not be detectable as 

far away as would be possible under 

quieter conditions and would itself be 

masked. The masking of communication 

signals by anthropogenic noise may be 

considered as a reduction in the 


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communication space of animals (e.g., 

Clark et al., 2009) and may result in 

energetic or other costs as animals 

change their vocalization behavior (e.g., 

Miller et al., 2000, Foote et al., 2004, 

Parks et al., 2007, Di Iorio and Clark, 

2010, Holt et al., 2009). Oceanside 

Harbor is used by commercial and 

recreational vessels, and background 

sound levels in the area are already 

elevated. Due to the transient nature of 

marine mammals to move and avoid 

disturbance, masking is not likely to 

have long-term impacts on marine 

mammal species within the proposed 

project area. 

Airborne Acoustic Effects—Pinnipeds 

that occur near the project site could be 

exposed to airborne sounds associated 

with pile driving and removal that have 

the potential to cause behavioral 

harassment, depending on their distance 

from piling activities. Cetaceans are not 

expected to be exposed to airborne 

sounds that would result in harassment 

as defined under the MMPA. 

Airborne noise would primarily be an 

issue for pinnipeds that are swimming 

or hauled out near the project site 

within the range of noise levels elevated 

above the acoustic criteria. We 

recognize that pinnipeds in the water 

could be exposed to airborne sound that 

may result in behavioral harassment 

when looking with their heads above 

water. Most likely, airborne sound 

would cause behavioral responses 

similar to those discussed above in 

relation to underwater sound. For 

instance, anthropogenic sound could 

cause hauled out pinnipeds to exhibit 

changes in their normal behavior, such 

as reduction in vocalizations, or cause 

them to temporarily abandon the area 

and move further from the source. 

However, these animals would likely 

previously have been ‘‘taken’’ because 

of exposure to underwater sound above 

the behavioral harassment thresholds, 

which are generally larger than those 

associated with airborne sound. Thus, 

the behavioral harassment of these 

animals is already accounted for in 

these estimates of potential take. 

Therefore, we do not believe that 

authorization of incidental take 

resulting from airborne sound for 

pinnipeds is warranted, and airborne 

sound is not discussed further. 

Marine Mammal Habitat Effects 

The City of Oceanside’s proposed 

construction activities could have 

localized, temporary impacts on marine 

mammal habitat, including prey, by 

increasing in-water SPLs and slightly 

decreasing water quality. Increased 

noise levels may affect acoustic habitat 

(see Masking above) and adversely affect 

marine mammal prey in the vicinity of 

the project area (see discussion below). 

During impact and vibratory pile 

driving or removal, elevated levels of 

underwater noise would ensonify the 

project area where both fishes and 

mammals occur and could affect 

foraging success. Additionally, marine 

mammals may avoid the area during 

construction, however, displacement 

due to noise is expected to be temporary 

and is not expected to result in longterm effects to the individuals or 

populations. Construction activities are 

expected to be of short duration (6 nonconsecutive days) and would likely 

have temporary impacts on marine 

mammal habitat through increases in 

underwater and airborne sound. 

A temporary and localized increase in 

turbidity near the seafloor would occur 

in the immediate area surrounding the 

area where piles are installed or 

removed, for example, if high-pressure 

water jetting is used. In general, 

turbidity associated with pile driving is 

localized to an approximately 7.6 m 

radius around the pile (Everitt et al., 

1980). Cetaceans are not expected to be 

close enough to the pile driving areas to 

experience effects of turbidity, and any 

pinnipeds could avoid localized areas of 

turbidity. Therefore, we expect the 

impact from increased turbidity levels 

to be discountable to marine mammals 

and do not discuss it further. 

In-Water Construction Effects on 

Potential Foraging Habitat—The area 

likely impacted by the proposed action 

is relatively small compared to the total 

available habitat in the area within and 

outside the harbor. The proposed 

project area is highly influenced by 

anthropogenic activities and provides 

limited foraging habitat for marine 

mammals. Furthermore, pile driving 

and removal at the proposed project site 

would not obstruct long-term 

movements or migration of marine 

mammals. 

Avoidance of the immediate area by 

potential prey (i.e., fish) due to the 

temporary loss of foraging habitat is also 

possible. The duration of fish and 

marine mammal avoidance of this area 

after pile driving stops is unknown but 

a rapid return to normal recruitment, 

distribution, and behavior is 

anticipated. Any behavioral avoidance 

by prey of the disturbed area would still 

leave significantly large areas of 

potential foraging habitat in the nearby 

vicinity, primarily outside the harbor. 

In-water Construction Effects on 

Potential Prey—Sound may affect 

marine mammals through impacts on 

the abundance, behavior, or distribution 

of prey species (e.g., crustaceans, 

cephalopods, fish, zooplankton, other 

marine mammals). Marine mammal 

prey varies by species, season, and 

location. Here, we describe studies 

regarding the effects of noise on known 

marine mammal prey. 

Fish utilize the soundscape and 

components of sound in their 

environment to perform important 

functions such as foraging, predator 

avoidance, mating, and spawning 

(Zelick et al., 1999, Fay, 2009). 

Depending on their hearing anatomy 

and peripheral sensory structures, 

which vary among species, fishes hear 

sounds using pressure and particle 

motion sensitivity capabilities and 

detect the motion of surrounding water 

(Fay et al., 2008). The potential effects 

of noise on fishes depends on the 

overlapping frequency range, distance 

from the sound source, water depth of 

exposure, and species-specific hearing 

sensitivity, anatomy, and physiology. 

Key impacts to fishes may include 

behavioral responses, hearing damage, 

barotrauma (pressure-related injuries), 

and mortality. 

Fish react to sounds which are 

especially strong and/or intermittent 

low-frequency sounds, and behavioral 

responses such as flight or avoidance 

are the most likely effects. Short 

duration, sharp sounds can cause overt 

or subtle changes in fish behavior and 

local distribution. The reaction of fish to 

noise depends on the physiological state 

of the fish, past exposures, motivation 

(e.g., feeding, spawning, migration), and 

other environmental factors. Hastings 

and Popper (2005) identified several 

studies that suggest fish may relocate to 

avoid certain areas of sound energy. 

Additional studies have documented 

effects of pile driving on fish, several of 

which are based on studies in support 

of large, multiyear bridge construction 

projects (e.g., Scholik and Yan, 2001, 

Popper and Hastings, 2009). Many 

studies have demonstrated that impulse 

sounds might affect the distribution and 

behavior of some fishes, potentially 

impacting foraging opportunities or 

increasing energetic costs (e.g., Pearson 

et al., 1992, Skalski et al., 1992, Santulli 

et al., 1999, Fewtrell and McCauley, 

2012, Paxton et al., 2017). In response 

to pile driving, Pacific sardines and 

northern anchovies (Engraulis mordax) 

may exhibit an immediate startle 

response to individual strikes but return 

to ‘‘normal’’ pre-strike behavior 

following the conclusion of pile driving 

with no evidence of injury as a result 

(see NAVFAC, 2014). However, some 

studies have shown no or slight reaction 

to impulse sounds (e.g., Wardle et al., 

2001, Popper et al., 2005, Jorgenson and 

Gyselman, 2009, Pen ̃ a et al., 2013). 


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SPLs of sufficient strength have been 

known to cause injury to fish and fish 

mortality. However, in most fish 

species, hair cells in the ear 

continuously regenerate and loss of 

auditory function likely is restored 

when damaged cells are replaced with 

new cells. Halvorsen et al. (2012b) 

showed that a TTS of 4–6 dB was 

recoverable within 24 hours for one 

species. Impacts would be most severe 

when the individual fish is close to the 

source and when the duration of 

exposure is long. Injury caused by 

barotrauma can range from slight to 

severe and can cause death, and is most 

likely for fish with swim bladders. 

Barotrauma injuries have been 

documented during controlled exposure 

to impact pile driving (Halvorsen et al., 

2012a, Casper et al., 2013) and the 

greatest potential effect on fish during 

the proposed project would occur 

during impact pile driving, if it is 

required. However, the duration of 

impact pile driving would be limited to 

a contingency in the event that vibratory 

driving does not satisfactorily install the 

pile depending on observed soil 

resistance. In-water construction 

activities would only occur during 

daylight hours allowing fish to forage 

and transit the project area at night. 

Vibratory pile driving may elicit 

behavioral reactions from fish such as 

temporary avoidance of the area but is 

unlikely to cause injuries to fish or have 

persistent effects on local fish 

populations. In addition, it should be 

noted that the area in question is lowquality habitat since it is already 

developed and experiences 

anthropogenic noise from vessel traffic. 

The most likely impact to fishes from 

pile driving and removal and 

construction activities at the project area 

would be temporary behavioral 

avoidance of the area. The duration of 

fish avoidance of this area after pile 

driving stops is unknown but a rapid 

return to normal recruitment, 

distribution, and behavior is 

anticipated. In general, impacts to 

marine mammal prey species are 

expected to be minor and temporary. 

Further, it is anticipated that 

preparation activities for pile driving or 

removal (i.e., positioning of the 

hammer) and upon initial startup of 

devices would cause fish to move away 

from the affected area where injuries 

may occur. Therefore, relatively small 

portions of the proposed project area 

would be affected for short periods of 

time, and the potential for effects on fish 

to occur would be temporary and 

limited to the duration of soundgenerating activities. 

In summary, given the short daily 

duration of sound associated with 

individual pile driving events and the 

relatively small area being affected, pile 

driving activities associated with the 

proposed action are not likely to have a 

permanent, adverse effect on any fish 

habitat or populations of fish species. 

Any behavioral avoidance by fish of the 

disturbed area would still leave 

significantly large potential areas for 

fish and marine mammal foraging in the 

nearby vicinity. Thus, we conclude that 

impacts of the specified activities are 

not likely to have more than short-term 

adverse effects on any prey habitat or 

populations of prey species. Further, 

any impacts to marine mammal habitat 

are not expected to result in significant 

or long-term consequences for 

individual marine mammals, or to 

contribute to adverse impacts on their 

populations. 

Estimated Take of Marine Mammals 

This section provides an estimate of 

the number of incidental takes proposed 

for authorization through this IHA, 

which will inform both NMFS’ 

consideration of ‘‘small numbers,’’ and 

the negligible impact determinations. 

Harassment is the only type of take 

expected to result from these activities. 

Except with respect to certain activities 

not pertinent here, section 3(18) of the 

MMPA defines ‘‘harassment’’ as any act 

of pursuit, torment, or annoyance, 

which (i) has the potential to injure a 

marine mammal or marine mammal 

stock in the wild (Level A harassment); 

or (ii) has the potential to disturb a 

marine mammal or marine mammal 

stock in the wild by causing disruption 

of behavioral patterns, including, but 

not limited to, migration, breathing, 

nursing, breeding, feeding, or sheltering 

(Level B harassment). 

Authorized takes would be by Level B 

harassment only in the form of 

disruption of behavioral patterns for 

individual marine mammals resulting 

from exposure to the acoustic sources. 

Based on the nature of the activity and 

the anticipated effectiveness of the 

mitigation measures (i.e., shutdown) 

discussed in detail below in the 

Proposed Mitigation section, Level A 

harassment is neither anticipated nor 

proposed to be authorized. 

As described previously, no serious 

injury or mortality is anticipated or 

proposed to be authorized for this 

activity. Below we describe how the 

proposed take numbers are estimated. 

For acoustic impacts, generally 

speaking, we estimate take by 

considering: (1) acoustic thresholds 

above which NMFS believes the best 

available science indicates marine 

mammals will be behaviorally harassed 

or incur some degree of permanent 

hearing impairment; (2) the area or 

volume of water that will be ensonified 

above these levels in a day; (3) the 

density or occurrence of marine 

mammals within these ensonified areas; 

and, (4) the number of days of activities. 

We note that while these factors can 

contribute to a basic calculation to 

provide an initial prediction of potential 

takes, additional information that can 

qualitatively inform take estimates is 

also sometimes available (e.g., previous 

monitoring results or average group 

size). Below, we describe the factors 

considered here in more detail and 

present the proposed take estimates. 

Acoustic Thresholds 

NMFS recommends the use of 

acoustic thresholds that identify the 

received level of underwater sound 

above which exposed marine mammals 

would be reasonably expected to be 

behaviorally harassed (equated to Level 

B harassment) or to incur PTS of some 

degree (equated to Level A harassment). 

Level B Harassment—Though 

significantly driven by received level, 

the onset of behavioral disturbance from 

anthropogenic noise exposure is also 

informed to varying degrees by other 

factors related to the source or exposure 

context (e.g., frequency, predictability, 

duty cycle, duration of the exposure, 

signal-to-noise ratio, distance to the 

source), the environment (e.g., 

bathymetry, other noises in the area, 

predators in the area), and the receiving 

animals (hearing, motivation, 

experience, demography, life stage, 

depth) and can be difficult to predict 

(e.g., Southall et al., 2007, Southall et 

al., 2021, Ellison et al., 2012). Based on 

what the available science indicates and 

the practical need to use a threshold 

based on a metric that is both 

predictable and measurable for most 

activities, NMFS typically uses a 

generalized acoustic threshold based on 

received level to estimate the onset of 

behavioral harassment. NMFS generally 

predicts that marine mammals are likely 

to be behaviorally harassed in a manner 

considered to be Level B harassment 

when exposed to underwater 

anthropogenic noise above root-meansquared pressure received levels (RMS 

SPL) of 120 dB (referenced to 1 

microPascal (re 1 mPa)) for continuous 

(e.g., vibratory pile driving, drilling) and 

above RMS SPL 160 dB re 1 mPa for nonexplosive impulsive (e.g., seismic 

airguns) or intermittent (e.g., scientific 

sonar) sources. Generally speaking, 

Level B harassment take estimates based 

on these behavioral harassment 

thresholds are expected to include any 


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likely takes by TTS as, in most cases, 

the likelihood of TTS occurs at 

distances from the source less than 

those at which behavioral harassment is 

likely. TTS of a sufficient degree can 

manifest as behavioral harassment as 

reduced hearing sensitivity and the 

potential reduced opportunities to 

detect important signals (e.g., 

conspecific communication, predators, 

prey) may result in changes in behavior 

patterns that would not otherwise occur. 

The City of Oceanside’s proposed 

construction activities includes the use 

of continuous (vibratory pile removal 

and installation) and, potentially, 

impulsive (impact pile installation) 

sources, and therefore the RMS SPL 

thresholds of 120 and 160 dB re 1 mPa 

are both applicable. 

Level A Harassment—NMFS’ 

Technical Guidance for Assessing the 

Effects of Anthropogenic Sound on 

Marine Mammal Hearing (Version 2.0) 

(Technical Guidance, 2018) identifies 

dual criteria to assess auditory injury 

(Level A harassment) to five different 

marine mammal groups (based on 

hearing sensitivity) as a result of 

exposure to noise from two different 

types of sources (impulsive or nonimpulsive). The City of Oceanside’s 

proposed activity includes the use of 

impulsive (impact hammer) and nonimpulsive (vibratory hammer) sources. 

These thresholds are provided in table 

4, below. The references, analysis, and 

methodology used in the development 

of the thresholds are described in 

NMFS’ 2018 Technical Guidance, which 

may be accessed at: https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/marinemammal-acoustic-technical-guidance. 

TABLE 4—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT

Hearing group 

PTS onset acoustic thresholds * (received level) 

Impulsive Non-impulsive 

Low-Frequency (LF) Cetaceans ...................................... Cell 1: Lpk,flat: 219 dB; LE,LF,24h: 183 dB. ........................ Cell 2: LE,LF,24h: 199 dB. 

Mid-Frequency (MF) Cetaceans ...................................... Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185 dB. ....................... Cell 4: LE,MF,24h: 198 dB. 

High-Frequency (HF) Cetaceans ..................................... Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155 dB. ....................... Cell 6: LE,HF,24h: 173 dB. 

Phocid Pinnipeds (PW) (Underwater) ............................. Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185 dB. ...................... Cell 8: LE,PW,24h: 201 dB. 

Otariid Pinnipeds (OW) (Underwater) ............................. Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203 dB. ...................... Cell 10: LE,OW,24h: 219 dB. 

* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should 

also be considered. 

Note: Peak sound pressure (Lpk) has a reference value of 1 μPa, and cumulative sound exposure level (LE) has a reference value of 1μPa2s. 

In this table, thresholds are abbreviated to reflect American National Standards Institute standards (ANSI 2013). However, peak sound pressure 

is defined by ANSI as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ‘‘flat’’ is being 

included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated 

with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF 

cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level 

thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for 

action proponents to indicate the conditions under which these acoustic thresholds will be exceeded. 

Ensonified Area 

Here, we describe operational and 

environmental parameters of the activity 

that are used in estimating the area 

ensonified above the acoustic 

thresholds, including source levels and 

transmission loss (TL) coefficient. 

Pile driving activities using an impact 

hammer as well as a vibratory hammer 

would generate underwater noise that 

could result in disturbance to marine 

mammals near the project area. A 

review of underwater sound 

measurements for similar projects was 

conducted to estimate the near-source 

sound levels for impact and vibratory 

pile driving and vibratory extraction. 

Source levels for proposed removal and 

installation activities derived from this 

review are shown in table 5. 

TABLE 5—PROJECT SOUND SOURCE LEVELS

Activity Method Pile size 

(inch, material) 

Peak SPL dB 

re 1 μPa 1

RMS SPL dB 

re 1 μPa 1

SEL dB 

re 1 μPa 1 Source 

Extraction ................. Vibratory ................... 16, concrete 2 ........... N/A 163 N/A NAVFAC SW, 2022. 

Installation ................ Vibratory ................... 18, steel ................... 196 158 N/A Caltrans, 2020. 

Installation ................ Impact ...................... 18, steel 3 ................. 200 185 175 Caltrans, 2020. 

Installation ................ Vibratory ................... 10, steel 4 ................. 171 155 N/A Illingworth and 

Rodkin, 2007. 

Note: All 18-inch round steel piles will be installed using both vibratory and impact driving, therefore, the total number of 18-inch piles proposed for use is 18. Use of 10-inch piles will be as temporary support, and will be driven and removed in the same day as the permanent 18- 

inch piles. 1As measured, or calculated, at 10 m (33 ft). 

2Proxy source levels provided by NMFS from Pier 6 Replacement Project, San Diego Bay (NAVFAC SW, 2022). 

3Analysis of pooled reported data provided by NMFS (Caltrans, 2020). 

4 In the absence of information on vibratory installation of 10-inch round steel piles, source data from 12-inch round steel piles (Illingworth and 

Rodkin, 2007) was used as a proxy source level. 

Level B Harassment Zone—TL is the 

decrease in acoustic intensity as an 

acoustic pressure wave propagates out 

from a source. TL parameters vary with 

frequency, temperature, sea conditions, 

current, source and receiver depth, 

water depth, water chemistry, and 

bottom composition topography. The 

general formula for underwater TL is: 

TL = B * Log10 (R1/R2), 

where: 

TL = transmission loss in dB; 

B = transmission loss coefficient; 

R1 = the distance of the modeled SPL from 

the driven pile; and 

R2 = the distance from the driven pile of the 


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initial measurement. 

The recommended TL coefficient for 

most nearshore environments is the 

practical spreading value of 15. This 

value results in an expected propagation 

environment that would lie between 

spherical and cylindrical spreading loss 

conditions, known as practical 

spreading, which is the most 

appropriate assumption for the City of 

Oceanside’s proposed activity in the 

absence of specific modeling and sitespecific information. Sound propagation 

in Oceanside Harbor is limited by 

physical structures and substantial 

sound would be confined within the 

harbor (see Figures 6–1, 6–2 in 

application). The Level A and Level B 

harassment isopleths for the City of 

Oceanside’s proposed activities are 

shown in table 6. 

TABLE 6—DISTANCE TO THE LEVEL A AND LEVEL B HARASSMENT THRESHOLDS FOR PROPOSED ACTIVITIES

Activity Method Pile size 

(inch, material) 

Level A 

threshold for 

MF 

(m) 

Level A 

threshold for 

PW 

(m) 

Level A 

threshold for 

OW 

(m) 

Level B 

harassment 

zone 

(m) 

Extraction ...................... Vibratory ...................... 16, concrete ................ 1.2 7.9 0.6 7,356 

Installation .................... Vibratory ...................... 18, steel ...................... 0.5 3.7 0.3 3,415 

Installation .................... Impact ......................... 18, steel ...................... 11.7 176.7 12.9 100 

Installation .................... Vibratory ...................... 10, steel ...................... 0.2 1.3 0.1 2,154 

Note: for impact pile driving, the single strike SEL was used to calculate distances to Level A harassment thresholds. 

Abbreviations: MF = mid-frequency cetaceans, PW = phocid pinnipeds, OW = otariid pinnipeds. 

Level A Harassment Zones—The 

ensonified area associated with Level A 

harassment is more technically 

challenging to predict due to the need 

to account for a duration component. 

Therefore, NMFS developed an optional 

User Spreadsheet tool to accompany the 

Technical Guidance that can be used to 

relatively simply predict an isopleth 

distance for use in conjunction with 

marine mammal density or occurrence 

to help predict potential takes. We note 

that because of some of the assumptions 

included in the methods underlying this 

optional tool, we anticipate that the 

resulting isopleth estimates are typically 

going to be overestimates of some 

degree, which may result in an 

overestimate of potential take by Level 

A harassment. However, this optional 

tool offers the best way to estimate 

isopleth distances when more 

sophisticated modeling methods are not 

available or practical. For stationary 

sources (i.e., vibratory and impact 

piling), the optional User Spreadsheet 

tool predicts the distance at which, if a 

marine mammal remained at that 

distance for the duration of the activity, 

it would be expected to incur PTS. 

Inputs used in the optional User 

Spreadsheet tool, and the resulting 

estimated isopleths, are reported in 

tables 6 and 7. The isopleths generated 

by the User Spreadsheet used the same 

TL coefficients as the Level B 

harassment isopleth calculations, as 

indicated above for each activity type. 

Inputs used in the User Spreadsheet 

(e.g., number of piles per day, duration 

and/or strikes per pile) are presented in 

table 1. The maximum RMS SPL, SEL, 

and peak SPL are reported in table 7. 

The cumulative SEL and peak SPL were 

used to calculate Level A harassment 

isopleths for vibratory pile driving and 

extraction activities, while the single 

strike SEL value was used to calculate 

Level A harassment isopleths for impact 

pile driving activity. 

TABLE 7—SOUND LEVELS USED FOR PREDICTING UNDERWATER SOUND IMPACTS

Activity Method Pile size 

(inch, material) 

Duration 

(hours/day) 

Peak SPL dB 

re 1 μPa 

RMS SPL dB 

re 1 μPa 

Single strike 

SEL dB re 

1 μPa2 sec 

Extraction ...................... Vibratory ...................... 16, concrete ................ 1.67 N/A 163 N/A 

Installation .................... Vibratory ...................... 18, steel ...................... 1.67 196 158 N/A 

Installation .................... Impact ......................... 18, steel ...................... 0.13 200 185 175 

Installation .................... Vibratory ...................... 10, steel ...................... 0.67 171 155 N/A 

Marine Mammal Occurrence 

In this section we provide information 

about the occurrence of marine 

mammals, including density or other 

relevant information which will inform 

the take calculations. 

Bottlenose Dolphin—Bottlenose 

dolphins can occur at any time of year 

in the waters around Oceanside Harbor. 

Based on previous monitoring (Merkel 

and Associates, Inc., 2022), an average 

of 6 bottlenose dolphins per day were 

observed with a maximum of 12 

individuals being observed on a single 

day. This higher peak of 12 individuals 

was used to calculate Level B 

harassment for bottlenose dolphin. 

Common Dolphin—Common 

dolphins are generally abundant in the 

outer coastal waters but are not known 

to occur regularly in Oceanside Harbor. 

Based on marine mammal monitoring 

by NAVFAC SW (2015), during El Nin ̃ o 

conditions an average of 8.5 common 

dolphins per day (rounded to nine per 

day) were observed in northwest San 

Diego Bay. This expected daily 

individual count was used to calculate 

the take by Level B harassment for 

common dolphins within Oceanside 

Harbor as no local data exists. 

Pacific White-Sided Dolphin—Pacific 

white-sided dolphins are commonly 

seen offshore of southern California but 

are not known to occur regularly in 

Oceanside Harbor. Based on the 

observations presented by NAVFAC SW 

(2015), during El Nin ̃ o conditions an 

average of 0.3 Pacific white-sided 

dolphins per day (rounded to one per 

day) were observed. This expected daily 

individual count was used to calculate 

the Level B harassment for Pacific 

white-sided dolphins. 

California Sea Lion—California sea 

lions are present in Oceanside Harbor 

year-round and numbers vary 

considerably. The daily estimate 

provided by the Oceanside Harbor 

Department is over 100 individuals. 

Limited counts from photographs and 


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spot counts average approximately 50 

individuals and are known to be 

incomplete estimates. Based on the 

variability in the number of sea lions 

present in the harbor, an estimate of 100 

sea lions per day was used to estimate 

take. 

Harbor Seal—Based on marine 

mammal monitoring by NAVFAC SW 

(2015), during El Nin ̃ o conditions an 

average of 2.5 harbor seals per day 

(rounded to three per day) were 

observed. This expected daily 

individual count was used to calculate 

the Level B harassment for harbor seals 

in Oceanside Harbor. 

Northern Elephant Seal—Due to 

increasing population size of northern 

elephant seals, presence in the Southern 

California Bight is considered a 

reasonable possibility (Carretta et al., 

2023). Based on marine mammal 

monitoring by NAVFAC SW (2015), an 

average of 0.1 northern elephant seals 

per day (rounded to one per day) were 

observed during El Nin ̃ o conditions. 

This expected daily individual count 

was used to calculate the Level B 

harassment for northern elephant seals 

in Oceanside Harbor. 

Take Estimation 

Here we describe how the information 

provided above is synthesized to 

produce a quantitative estimate of the 

take that is reasonably likely to occur 

and proposed for authorization. 

No take by Level A harassment is 

proposed for any species of marine 

mammal due to the small zone sizes for 

most taxa, and the low likelihood that 

an animal would approach during inwater construction or remain within the 

Level A harassment isopleth long 

enough to incur PTS during the 

specified activities. Proposed shutdown 

zones would encompass the extent of 

the estimated Level A harassment 

isopleths (180 m for phocid pinnipeds 

during impact driving, 15 m for all other 

species and activities) and are expected 

to be effective at avoiding Level A 

harassment for all species. Given the 

locations of Protected Species Observers 

(PSOs) described in the Proposed 

Monitoring and Reporting section, in 

conjunction with the City of 

Oceanside’s proposed shutdown 

mitigation measure, NMFS agrees that 

monitoring and shutdown measures are 

likely to be successful at avoiding take 

by Level A harassment. 

Incidental take by Level B harassment 

was estimated for each species by 

multiplying the expected average 

number of individuals per day by the 

number of work days (6 days; table 8). 

Take estimates for each species were 

calculated by multiplying the estimated 

site-specific abundance of each species 

by the area of impact where noise levels 

exceed acoustic thresholds for marine 

mammals during active each type of 

piling activity (vibratory removal, 

vibratory driving, impact driving) and 

pile size (16 inch concrete, 18 inch 

steel, 10 inch steel). Estimated daily 

exposures for each species were based 

on evaluation of the potential presence 

of each marine mammal species using 

historical occurrence from Oceanside 

Harbor (Merkel and Associates, Inc., 

2022; Merkel and Associates, Inc., 

2023). 

Estimated Take = Expected Average 

Individuals per Day × Number of 

Work Days 

Due to a paucity of marine mammal 

occurrence data within Oceanside 

Harbor, and with the probability of El 

Nin ̃ o conditions persisting throughout 

2024 (https://www.cpc.ncep.noaa.gov/ 

products/analysis_monitoring/enso_

advisory/ensodisc.shtml), four species 

of marine mammal (common dolphin, 

Pacific white-sided dolphin, harbor seal, 

northern elephant seal) that are unlikely 

to occur within a semi-enclosed harbor 

environment were included to account 

for a potential increase in occurrence 

that has been previously documented 

for those species under similar 

climatological conditions (NAVFAC 

SW, 2015). 

TABLE 8—ESTIMATED TAKE BY LEVEL B HARASSMENT PROPOSED FOR AUTHORIZATION

Common name Scientific name Stock 

Expected 

average 

individuals 

per day 

Maximum 

estimated 

Level B 

harassment 

takes 

Estimated 

takes as a 

percentage of 

population 

Bottlenose dolphin 1 ............... Tursiops truncatus ................ California Coastal ................. 12 72 15.9 

Common dolphin (longbeaked) 2.Delphinus capensis .............. California ............................... * 9 * 54 <1 

Common dolphin (shortbeaked) 2.Delphinus delphis ................. California/Oregon/Washington.* 9 * 54 <1 

Pacific white-sided dolphin 2 .. Lagenorhynchus obliquidens California/Oregon/Washington—Northern and 

Southern.

1 6 <1 

California sea lion 3 ................ Zalophus californianus .......... U.S. ....................................... 100 600 <1 

Harbor seal 2 .......................... Phoca vitulina richardii ......... California ............................... 3 18 <1 

Northern elephant seal 2 ........ Mirounga angustirostris ........ California breeding ............... 1 6 <1 

1Average daily counts based on observations during Oceanside Harbor Dredging 2022 Project Monitoring, rounded up to nearest individual 

count (Merkel and Associates Inc., 2022). 2Average daily counts based on observations during Year 2 of Navy Base Point Loma’s Fuel Pier Replacement Project Monitoring, rounded up 

to nearest individual count (NAVFAC SW, 2015). 3 Reported high estimate of sea lions observed on pinniped float by Oceanside Harbor District staff. 

* A total of 54 takes are estimated and may be attributed to either long- or short-beaked common dolphin species. 

Proposed Mitigation 

In order to issue an IHA under section 

101(a)(5)(D) of the MMPA, NMFS must 

set forth the permissible methods of 

taking pursuant to the activity, and 

other means of effecting the least 

practicable impact on the species or 

stock and its habitat, paying particular 

attention to rookeries, mating grounds, 

and areas of similar significance, and on 

the availability of the species or stock 

for taking for certain subsistence uses 

(latter not applicable for this action). 

NMFS regulations require applicants for 

incidental take authorizations to include 

information about the availability and 

feasibility (economic and technological) 

of equipment, methods, and manner of 

conducting the activity or other means 

of effecting the least practicable adverse 

impact upon the affected species or 

stocks, and their habitat (50 CFR 

216.104(a)(11)). 


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In evaluating how mitigation may or 

may not be appropriate to ensure the 

least practicable adverse impact on 

species or stocks and their habitat, as 

well as subsistence uses where 

applicable, NMFS considers two 

primary factors: 

(1) The manner in which, and the 

degree to which, the successful 

implementation of the measure(s) is 

expected to reduce impacts to marine 

mammals, marine mammal species or 

stocks, and their habitat. This considers 

the nature of the potential adverse 

impact being mitigated (likelihood, 

scope, range). It further considers the 

likelihood that the measure will be 

effective if implemented (probability of 

accomplishing the mitigating result if 

implemented as planned), the 

likelihood of effective implementation 

(probability implemented as planned); 

and 

(2) The practicability of the measures 

for applicant implementation, which 

may consider such things as cost, and 

impact on operations. 

The City of Oceanside must ensure 

that construction supervisors and crews, 

the monitoring team, and relevant staff/ 

contractors are trained prior to the start 

of all piling activities so that 

responsibilities, communication 

procedures, monitoring protocols, and 

operational procedures are clearly 

understood. New personnel joining 

during the project must be trained prior 

to commencing work. 

Timing Restrictions 

All piling activities would be 

conducted during daylight hours, 

generally between 45 minutes postsunrise and 45 minutes pre-sunset. All 

piling would occur in March 2024 and/ 

or September 2024 through February 

2025, when the likelihood of ESA-listed 

California least tern breeding and 

nesting in the work area is minimal, as 

proposed by the City of Oceanside. 

Protected Species Observers 

The placement of PSOs during all pile 

driving activities (described in the 

Proposed Monitoring and Reporting 

section) would ensure that the entire 

shutdown zone is visible. Should 

environmental conditions deteriorate 

such that the entire shutdown zone 

would not be visible (e.g., fog, heavy 

rain), pile driving would be delayed 

until the PSO is confident marine 

mammals within the shutdown zone 

could be detected. 

PSOs would monitor the full 

shutdown zones and the Level B 

harassment zones to the extent 

practicable. Monitoring zones provide 

utility for observing by establishing 

monitoring protocols for areas adjacent 

to the shutdown zones. Monitoring 

zones enable observers to be aware of 

and communicate the presence of 

marine mammals in the project areas 

outside the shutdown zones and thus 

prepare for a potential cessation of 

activity should the animal enter the 

shutdown zone. 

Pre- and Post-Activity Monitoring 

Monitoring must take place from 30 

minutes prior to initiation of pile 

driving activities (i.e., pre-clearance 

monitoring) through 30 minutes postcompletion of pile driving. Prior to the 

start of daily in-water construction 

activity, or whenever a break in pile 

driving of 30 minutes or longer occurs, 

PSOs would observe the shutdown and 

monitoring zones for a period of 30 

minutes. The shutdown zone would be 

considered cleared when a marine 

mammal has not been observed within 

the zone for a 30-minute period. If a 

marine mammal is observed within the 

shutdown zones listed in table 9, pile 

driving activity would be delayed or 

halted. If work ceases for more than 30 

minutes, the pre-activity monitoring of 

the shutdown zones would commence. 

A determination that the shutdown zone 

is clear must be made during a period 

of good visibility (i.e., the entire 

shutdown zone and surrounding waters 

must be visible to the naked eye). 

Soft-Start Procedures for Impact Driving 

Soft-start procedures provide 

additional protection to marine 

mammals by providing warning and/or 

giving marine mammals a chance to 

leave the area prior to the hammer 

operating at full capacity. If impact pile 

driving is necessary to achieve required 

tip elevation, City of Oceanside staff 

and/or contractors would be required to 

provide an initial set of three strikes 

from the hammer at reduced energy, 

followed by a 30-second waiting period, 

then two subsequent reduced-energy 

strike sets. Soft-start would be 

implemented at the start of each day’s 

impact pile driving and at any time 

following cessation of impact pile 

driving for a period of 30 minutes or 

longer. 

Shutdown Zones 

The City of Oceanside must establish 

shutdown zones for all pile driving 

activities. The purpose of a shutdown 

zone is generally to define an area 

within which shutdown of the activity 

would occur upon sighting of a marine 

mammal (or in anticipation of an animal 

entering the defined area). Shutdown 

zones would be based upon the Level A 

harassment thresholds for each pile 

size/type and driving method where 

applicable, as shown in table 6. During 

all in-water piling activities, the City of 

Oceanside has proposed to implement a 

buffered 15 m shutdown zone, with the 

exception of a 180 m shutdown zone for 

phocids during the use of impact pile 

driving of 18-inch piles. These distances 

exceed the estimated Level A 

harassment isopleths described in table 

6. Adherence to this expanded 

shutdown zone will avoid the potential 

for the take of phocids by Level A 

harassment during impact pile driving. 

For pile driving, the radii of the 

shutdown zones are rounded to the next 

largest 10 m interval in comparison to 

the Level A harassment isopleth for 

each activity type. If a marine mammal 

is observed entering, or detected within, 

a shutdown zone during pile driving 

activity, the activity must be stopped 

until there is visual confirmation that 

the animal has left the zone or the 

animal is not sighted for a period of 15 

minutes. Proposed shutdown zones for 

each activity type are shown in Table 9. 

All marine mammals would be 

monitored in the Level B harassment 

zones and throughout the area as far as 

visual monitoring can take place. If a 

marine mammal enters the Level B 

harassment zone, in-water activities 

would continue and PSOs would 

document the animal’s presence within 

the estimated harassment zone. 

TABLE 9—PROPOSED SHUTDOWN AND HARASSMENT ZONES

Activity Method Pile size 

(inch, material) 

Shutdown 

zone for MF 

(m) 

Shutdown 

zone for PW 

(m) 

Shutdown 

zone for OW 

(m) 

Harassment 

zone 

(m) 

Extraction ...................... Vibratory ...................... 16, concrete ................ 15 15 15 7,360 

Installation .................... Vibratory ...................... 18, steel ...................... 15 15 15 3,420 

Installation .................... Impact ......................... 18, steel ...................... 15 180 15 100 

Installation .................... Vibratory ...................... 10, steel ...................... 15 15 15 2,160 


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Based on our evaluation of the City of 

Oceanside’s proposed measures, NMFS 

has preliminarily determined that the 

proposed mitigation measures provide 

the means of effecting the least 

practicable impact on the affected 

species or stocks and their habitat, 

paying particular attention to rookeries, 

mating grounds, and areas of similar 

significance. 

Proposed Monitoring and Reporting 

In order to issue an IHA for an 

activity, section 101(a)(5)(D) of the 

MMPA states that NMFS must set forth 

requirements pertaining to the 

monitoring and reporting of such taking. 

The MMPA implementing regulations at 

50 CFR 216.104(a)(13) indicate that 

requests for authorizations must include 

the suggested means of accomplishing 

the necessary monitoring and reporting 

that will result in increased knowledge 

of the species and of the level of taking 

or impacts on populations of marine 

mammals that are expected to be 

present while conducting the activities. 

Effective reporting is critical both to 

compliance as well as ensuring that the 

most value is obtained from the required 

monitoring. 

Monitoring and reporting 

requirements prescribed by NMFS 

should contribute to improved 

understanding of one or more of the 

following: 

• Occurrence of marine mammal 

species or stocks in the area in which 

take is anticipated (e.g., presence, 

abundance, distribution, density); 

• Nature, scope, or context of likely 

marine mammal exposure to potential 

stressors/impacts (individual or 

cumulative, acute or chronic), through 

better understanding of: (1) action or 

environment (e.g., source 

characterization, propagation, ambient 

noise); (2) affected species (e.g., life 

history, dive patterns); (3) co-occurrence 

of marine mammal species with the 

activity; or (4) biological or behavioral 

context of exposure (e.g., age, calving or 

feeding areas); 

• Individual marine mammal 

responses (behavioral or physiological) 

to acoustic stressors (acute, chronic, or 

cumulative), other stressors, or 

cumulative impacts from multiple 

stressors; 

• How anticipated responses to 

stressors impact either: (1) long-term 

fitness and survival of individual 

marine mammals; or (2) populations, 

species, or stocks; 

• Effects on marine mammal habitat 

(e.g., marine mammal prey species, 

acoustic habitat, or other important 

physical components of marine 

mammal habitat); and 

• Mitigation and monitoring 

effectiveness. 

Visual Monitoring 

Marine mammal monitoring must be 

conducted in accordance with the 

conditions in this section and this IHA. 

Marine mammal monitoring during pile 

driving activities would be conducted 

by two PSOs meeting NMFS’ standards 

and in a manner consistent with the 

following: 

• PSOs must be independent of the 

activity contractor (for example, 

employed by a subcontractor) and have 

no other assigned tasks during 

monitoring periods; 

• At least one PSO would have prior 

experience performing the duties of a 

PSO during construction activity 

pursuant to a NMFS-issued incidental 

take authorization; 

• Other PSOs may substitute other 

relevant experience, education (degree 

in biological science or related field), or 

training for prior experience performing 

the duties of a PSO during construction 

activity pursuant to a NMFS-issued 

incidental take authorization; 

• Where a team of three or more PSOs 

is required, a lead observer or 

monitoring coordinator must be 

designated. The lead observer must have 

prior experience performing the duties 

of a PSO during construction activity 

pursuant to a NMFS-issued incidental 

take authorization; and 

• PSOs must be approved by NMFS 

prior to beginning any activity subject to 

the IHA. 

PSOs should have the following 

additional qualifications: 

• Ability to conduct field 

observations and collect data according 

to assigned protocols; 

• Experience or training in the field 

identification of marine mammals, 

including the identification of 

behaviors; 

• Sufficient training, orientation, or 

experience with the construction 

operation to provide for personal safety 

during observations; 

• Writing skills sufficient to prepare a 

report of observations including but not 

limited to the number and species of 

marine mammals observed; dates and 

times when in-water construction 

activities were conducted; dates, times, 

and reason for implementation of 

mitigation (or why mitigation was not 

implemented when required); and 

marine mammal behavior; and 

• Ability to communicate orally, by 

radio or in person, with project 

personnel to provide real-time 

information on marine mammals 

observed in the area as necessary. 

The City of Oceanside would have 

two PSOs stationed at the best possible 

vantage points in the project area to 

monitor during all pile driving 

activities. Monitoring would occur from 

elevated locations along the shoreline 

where the entire shutdown zones are 

visible. PSOs would be equipped with 

high quality binoculars for monitoring 

and radios or cells phones for 

maintaining contact with work crews. 

Monitoring would be conducted 30 

minutes before, during, and 30 minutes 

after all in-water construction activities. 

In addition, PSOs would record all 

incidents of marine mammal 

occurrence, regardless of distance from 

activity, and would document any 

behavioral reactions in concert with 

distance from piles being driven or 

removed. Pile driving activities include 

the time to install or remove a single 

pile or series of piles, as long as the time 

elapsed between uses of the pile driving 

equipment is no more than 30 minutes. 

Reporting 

The City of Oceanside will provide 

the following reporting as necessary 

during active pile driving activities: 

• The applicant will report any 

observed injury or mortality as soon as 

feasible and in accordance with NMFS’ 

standard reporting guidelines. Reports 

will be made by phone (866–767–6114) 

and by email 

(PR.ITP.MonitoringReports@noaa.gov) 

and will include the following: 

Æ Time, date, and location (latitude/ 

longitude) of the first discovery (and 

updated location information if known 

and applicable); 

Æ Species identification (if known) or 

description of the animal(s) involved; 

Æ Condition of the animal(s) 

(including carcass condition if the 

animal is dead); 

Æ Observed behaviors of the 

animal(s), if alive; 

Æ If available, photographs or video 

footage of the animal(s); and 

Æ General circumstances under which 

the animal was discovered; 

• An annual report summarizing the 

prior year’s activities will be provided 

that fully documents the methods and 

monitoring protocols, summarizes the 

data recorded during monitoring, 

estimates the number of listed marine 

mammals that may have been 

incidentally taken during project pile 

driving, and provides an interpretation 

of the results and effectiveness of all 

monitoring tasks. The annual draft 

report will be provided no later than 90 

days following completion of 

construction activities. Any 

recommendations made by NMFS will 

be addressed in the final report, due 


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after the IHA expires and including a 

summary of all monitoring activities, 

prior to acceptance by NMFS. Final 

reports will follow a standardized 

format for PSO reporting from activities 

requiring marine mammal mitigation 

and monitoring; and 

• All PSOs will use a standardized 

data entry format (see Monitoring Plan). 

Negligible Impact Analysis and 

Determination 

NMFS has defined negligible impact 

as an impact resulting from the 

specified activity that cannot be 

reasonably expected to, and is not 

reasonably likely to, adversely affect the 

species or stock through effects on 

annual rates of recruitment or survival 

(50 CFR 216.103). A negligible impact 

finding is based on the lack of likely 

adverse effects on annual rates of 

recruitment or survival (i.e., populationlevel effects). An estimate of the number 

of takes alone is not enough information 

on which to base an impact 

determination. In addition to 

considering estimates of the number of 

marine mammals that might be ‘‘taken’’ 

through harassment, NMFS considers 

other factors, such as the likely nature 

of any impacts or responses (e.g., 

intensity, duration), the context of any 

impacts or responses (e.g., critical 

reproductive time or location, foraging 

impacts affecting energetics), as well as 

effects on habitat, and the likely 

effectiveness of the mitigation. We also 

assess the number, intensity, and 

context of estimated takes by evaluating 

this information relative to population 

status. Consistent with the 1989 

preamble for NMFS’ implementing 

regulations (54 FR 40338; September 29, 

1989), the impacts from other past and 

ongoing anthropogenic activities are 

incorporated into this analysis via their 

impacts on the baseline (e.g., as 

reflected in the regulatory status of the 

species, population size and growth rate 

where known, ongoing sources of 

human-caused mortality, or ambient 

noise levels). 

To avoid repetition, the discussion of 

our analysis applies to all the species 

listed in table 2, given that the 

anticipated effects of this activity on 

these different marine mammal stocks 

are expected to be similar. There is little 

information about the nature or severity 

of the impacts, or the size, status, or 

structure of any of these species or 

stocks that would lead to a different 

analysis for this activity. 

Level A harassment is extremely 

unlikely given the small size of the 

Level A harassment isopleths and the 

required mitigation measures designed 

to minimize the possibility of injury to 

marine mammals (see Proposed 

Mitigation section). No mortality is 

anticipated given the nature of the 

activity. 

Pile installation and removal 

activities are likely to result in the Level 

B harassment of marine mammals that 

move into the ensonified zone, 

primarily in the form of disturbance or 

displacement of marine mammals. 

Take would occur within a limited, 

confined area of each stock’s range. 

Level B harassment would be reduced to 

the level of least practicable adverse 

impact through use of mitigation 

measures described herein. Further, the 

amount of take authorized is extremely 

small when compared to stock 

abundance. 

No marine mammal stocks for which 

incidental take authorization is 

proposed are listed as threatened or 

endangered under the ESA or 

determined to be strategic or depleted 

under the MMPA. The relatively low 

marine mammal occurrences in the area, 

small shutdown zones, and proposed 

monitoring make injury takes of marine 

mammals unlikely. The shutdown zones 

would be thoroughly monitored before 

the proposed vibratory pile installation 

and removal begins, and construction 

activities would be postponed if a 

marine mammal is sighted within the 

shutdown zone. There is a high 

likelihood that marine mammals would 

be detected by trained observers under 

environmental conditions described for 

the proposed project. Limiting 

construction activities to daylight hours 

would also increase detectability of 

marine mammals in the area. Therefore, 

the proposed mitigation and monitoring 

measures are expected to eliminate the 

potential for injury and Level A 

harassment as well as reduce the 

amount and intensity for Level B 

behavioral harassment. Furthermore, the 

pile installation and removal activities 

analyzed here are similar to, or less 

impactful than, numerous construction 

activities conducted in other similar 

locations which have occurred with no 

reported injuries or mortality to marine 

mammals, and no known long-term 

adverse consequences from behavioral 

harassment. 

Anticipated and authorized takes are 

expected to be limited to short-term 

Level B harassment (behavioral 

disturbance) as construction activities 

will occur over the course of 5–6 

months. Effects on individuals taken by 

Level B harassment, based upon reports 

in the literature as well as monitoring 

from other similar activities, may 

include increased swimming speeds, 

increased surfacing time, or decreased 

foraging (e.g., NAVFAC SW, 2018). 

Individual animals, even if taken 

multiple times, would likely move away 

from the sound source and be 

temporarily displaced from the area due 

to elevated noise level during pile 

removal. Marine mammals could also 

experience TTS if they move into the 

Level B harassment monitoring zone. 

TTS is a temporary loss of hearing 

sensitivity when exposed to loud sound, 

and, given the likely levels and duration 

of exposure to pile driving, any shift of 

the hearing threshold is expected to 

recover completely within minutes to 

hours. While TTS could occur, it is not 

considered a likely outcome of this 

activity. 

Given the limited number of total 

predicted exposures, no individual 

marine mammals of any species, with 

the possible exception of California sea 

lions, would be expected to be taken on 

more than a few days during the 

construction activities. California sea 

lions are relatively common in the area, 

and potential takes would likely involve 

sea lions loafing on, or in the vicinity of, 

physical structures or moving through 

the area en route to foraging areas or 

structures where they haul out. 

Relocation of the float where they 

frequently haul out is expected to 

reduce both the number of sea lions 

present in the area during construction 

and also the likelihood that they may be 

repeatedly impacted. 

The proposed project is not expected 

to have significant adverse effects on 

marine mammal habitat. There are no 

Biologically Important Areas or ESAdesignated critical habitat within the 

project area, and the proposed activities 

would not permanently modify existing 

marine mammal habitat. The activities 

may cause fish to leave the area 

temporarily which could impact marine 

mammals’ foraging opportunities in a 

limited portion of the foraging range. 

However, due to the short duration of 

the proposed activities and the 

relatively small area of affected habitat, 

the impacts to marine mammal habitat 

are not expected to cause significant or 

long-term negative consequences. 

In combination, we believe that these 

factors, as well as the available body of 

evidence from other similar activities, 

demonstrate that the potential effects of 

the specified activities would have only 

minor, short-term effects on individuals. 

The specified activities are not expected 

to impact reproduction or survival of 

any individual marine mammals, much 

less affect rates of recruitment or 

survival and would therefore not result 

in population-level impacts. 

In summary and as described above, 

the following factors primarily support 

our preliminary determination that the 


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impacts resulting from this activity are 

not expected to adversely affect any of 

the species or stocks through effects on 

annual rates of recruitment or survival: 

• No serious injury or mortality, or 

Level A harassment, is anticipated or 

authorized; 

• The specified activities are of a very 

short duration and associated ensonified 

areas are very small relative to the 

overall habitat ranges of both species; 

• The project area does not overlap 

with known BIAs or ESA-designated 

critical habitat; 

• Significant or long-term effects to 

marine mammal habitat are not 

anticipated; and 

• Proposed mitigation measures are 

expected to reduce the effects of the 

specified activity to the level of least 

practicable adverse impact. 

Based on the analysis contained 

herein of the likely effects of the 

specified activity on marine mammals 

and their habitat, and taking into 

consideration the implementation of the 

proposed monitoring and mitigation 

measures, NMFS preliminarily finds 

that the total marine mammal take from 

the proposed activity will have a 

negligible impact on all affected marine 

mammal species or stocks. 

Small Numbers 

As noted previously, only take of 

small numbers of marine mammals may 

be authorized under sections 

101(a)(5)(A) and (D) of the MMPA for 

specified activities other than military 

readiness activities. The MMPA does 

not define small numbers and so, in 

practice, where estimated numbers are 

available, NMFS compares the number 

of individuals taken to the most 

appropriate estimation of abundance of 

the relevant species or stock in our 

determination of whether an 

authorization is limited to small 

numbers of marine mammals. When the 

predicted number of individuals to be 

taken is fewer than one-third of the 

species or stock abundance, the take is 

considered to be of small numbers. 

Additionally, other qualitative factors 

may be considered in the analysis, such 

as the temporal or spatial scale of the 

activities. 

The amount of take NMFS has 

authorized is below one-third of the 

estimated stock abundances for all 

seven species (see table 8). For all but 

one species, the proposed take of 

individuals is less than 1 percent of the 

abundance of the affected stock (with 

the exception for bottlenose dolphins at 

less than 16 percent). This is likely a 

conservative estimate because it 

assumes all takes are of different 

individual animals, which is likely not 

the case. Some individuals may return 

multiple times in a day, but PSOs would 

count them as separate takes if they 

cannot be individually identified. 

Based on the analysis contained 

herein of the proposed activity 

(including the proposed mitigation and 

monitoring measures) and the 

anticipated take of marine mammals, 

NMFS preliminarily finds that small 

numbers of marine mammals would be 

taken relative to the population size of 

the affected species or stocks. 

Unmitigable Adverse Impact Analysis 

and Determination 

There are no relevant subsistence uses 

of the affected marine mammal stocks or 

species implicated by this action. 

Therefore, NMFS has determined that 

the total taking of affected species or 

stocks would not have an unmitigable 

adverse impact on the availability of 

such species or stocks for taking for 

subsistence purposes. 

Endangered Species Act 

Section 7(a)(2) of the ESA of 1973 (16 

U.S.C. 1531 et seq.) requires that each 

Federal agency insure that any action it 

authorizes, funds, or carries out is not 

likely to jeopardize the continued 

existence of any endangered or 

threatened species or result in the 

destruction or adverse modification of 

designated critical habitat. To ensure 

ESA compliance for the issuance of 

IHAs, NMFS consults internally 

whenever we propose to authorize take 

for endangered or threatened species. 

No incidental take of ESA-listed 

species is proposed for authorization or 

expected to result from this activity. 

Therefore, NMFS has determined that 

formal consultation under section 7 of 

the ESA is not required for this action. 

Proposed Authorization 

As a result of these preliminary 

determinations, NMFS proposes to issue 

an IHA to the City of Oceanside for 

conducting pile removal and driving in 

Oceanside Harbor, Oceanside, CA, 

provided the previously mentioned 

mitigation, monitoring, and reporting 

requirements are incorporated. A draft 

of the proposed IHA can be found at: 

https://www.fisheries.noaa.gov/ 

national/marine-mammal-protection/ 

incidental-take-authorizationsconstruction-activities. 

Request for Public Comments 

We request comment on our analyses, 

the proposed authorization, and any 

other aspect of this notice of proposed 

IHA for the proposed construction 

project. We also request comment on the 

potential renewal of this proposed IHA 

as described in the paragraph below. 

Please include with your comments any 

supporting data or literature citations to 

help inform decisions on the request for 

this IHA or a subsequent renewal IHA. 

On a case-by-case basis, NMFS may 

issue a one-time, one-year renewal IHA 

following notice to the public providing 

an additional 15 days for public 

comments when (1) up to another year 

of identical or nearly identical activities 

as described in the Description of 

Proposed Activity section of this notice 

is planned or (2) the activities as 

described in the Description of 

Proposed Activity section of this notice 

would not be completed by the time the 

IHA expires and a renewal would allow 

for completion of the activities beyond 

that described in the Dates and Duration 

section of this notice, provided all of the 

following conditions are met: 

• A request for renewal is received no 

later than 60 days prior to the needed 

renewal IHA effective date (recognizing 

that the renewal IHA expiration date 

cannot extend beyond one year from 

expiration of the initial IHA); and 

• The request for renewal must 

include the following: 

(1) An explanation that the activities 

to be conducted under the requested 

renewal IHA are identical to the 

activities analyzed under the initial 

IHA, are a subset of the activities, or 

include changes so minor (e.g., 

reduction in pile size) that the changes 

do not affect the previous analyses, 

mitigation and monitoring 

requirements, or take estimates (with 

the exception of reducing the type or 

amount of take); and 

(2) A preliminary monitoring report 

showing the results of the required 

monitoring to date and an explanation 

showing that the monitoring results do 

not indicate impacts of a scale or nature 

not previously analyzed or authorized. 

Upon review of the request for 

renewal, the status of the affected 

species or stocks, and any other 

pertinent information, NMFS 

determines that there are no more than 

minor changes in the activities, the 

mitigation and monitoring measures 

will remain the same and appropriate, 

and the findings in the initial IHA 

remain valid. 

Dated: November 20, 2023. 

Kimberly Damon-Randall, 

Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2023–26158 Filed 11–27–23; 8:45 am] 

BILLING CODE 3510–22–P 


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